acid and bases

Question 1

definition of acids

Answer 1

substance that dissociates or ionises to form h+ ions when dissolved in water

Question 2

acids + metal

Answer 2

salt and hydrogen

Question 3

acid + metal carbonate

Answer 3

salt, water, co2

Question 4

acid + metal oxides/ hydroxides

Answer 4

salt and water

Question 5

why can strong acids conduct electricity

Answer 5

dissociate in water to form solutions that can conduct electricity due to the presence of mobile ions that act as mobile charge carriers

Question 6

definition of a base

Answer 6

substance that reacts with an acid to produce salt and water only (+metal oxides & hydroxides)

Question 7

alkali + acid

Answer 7

salt + wwater

Question 8

alkali + ammonium salt

Answer 8

ammonia + water + salt

Question 9

special characteristic of lead sulfate, calcium sulfate, barium sulfate

Answer 9

the initial reaction between lead and acid produces a layer of lead XX which are insoluble in water and non porous, and quickly forms a coating around the metal. the coating prevents lead from further reacting with the acid

Question 10

reaction between acid and alkali

Answer 10

neutralisation

Question 11

acids + sodium sulfite

Answer 11

sodium salt + sulfur dioxide + water

Question 12

test for sulfur dioxide gas

Answer 12

place a strip of filter paper soaked in acidified potassium manganate (VII) solution in gas sample, if present, purple-> colourless

Question 13

test for ammonia

Answer 13

moist red litmus -> blue

Question 14

why slaked lime + ammonium nitrate not used at the same time?

Answer 14

ca(oh)2 reacts with nhno3, releasing ammonia gas which escapes from the soil, resulting in a loss of nitrogen from the soil

Question 15

what is sulfuric acid used for

Answer 15

manufacture of fertilisers, detergents

Question 16

hydrochloric acid

Answer 16

cleaning agent

Question 17

use of magnesium oxide

Answer 17

antacid

Question 18

magnesium hydroxide

Answer 18

toothpaste

Question 19

strength of acid

Answer 19

extent to which an acid or base dissociates when dissolves in water

Question 20

ionic compounds as strong electrolytes

Answer 20

when they dissolve in water, the cations and OH- ions break apart from the giant ionic lattice structure to move independently and act as mobile charge carriers

Question 21

weak base -> bad conductor of electricity?

Answer 21

weak bases only dissociate partially in water, causing them to contain a relatively lower concentration of mobile charge carriers, thus they are weak electrolytes

Question 22

definition of concentration

Answer 22

amount of substance dissolved in a fixed volume of solution

Question 23

strength vs concentration

Answer 23

strength - extent of dissociation
concentration - amount of solute dissolved in solvent

Question 24

dibasic vs monobasic -> concentration of H+

Answer 24

template : Both acids have the same concentration and strength, however, basicity of acid differs. sulphuric acid is a dibasic acid and produces xx concentration of H+ ions, but hbl is a monobasic acid and produces a lower concentration of h+ ions…

Question 25

ph indicators

Answer 25

methyl orange ( red - yellow, 3-5) screened methyl orange (pink - green, 3-5) thymol blue (yellow - blue, 8-10) phenolphthalein (colourless - pink, 8-10)

Question 26

types of oxides

Answer 26

basic amphoteric acidic neutral

Question 27

basic oxides

Answer 27

reacts only with acid to form salt and water all METAL OXIDES

Question 28

amphoteric oxides

Answer 28

react with acid and alkalis to form salt and water LAZ ( Lead oxide, aluminium oxide, zinc oxide)

Question 29

acidic oxides

Answer 29

react with bases to form salt and water NON METAL POLYOXIDE

Question 30

neutral oxides

Answer 30

do not react with an acid or a base NON METAL MONOXIDE

Question 31

definition of air pollution

Answer 31

where air contains a high concentration of chemicals that may harm living things or damage non living things

Question 32

Carbon monoxide is from

Answer 32

the incomplete combustion of petrol in car engines

Question 33

sulfur dioxide is from

Answer 33

fossil fuels that are burnt, and volcanic eruptions

Question 34

oxides of nitrogen

Answer 34

where temp is v high, nitrogen combines with oxygen to from nitrogen monoxide

Question 35

unbury hydrocarbons are from

Answer 35

car exhaust fumes and chemical plants

Question 36

effects of CO

Answer 36

react with haemoglobin to form carboxyhaemoglobin, which reduces the ability of haemoglobin to transport o2 to rest of body causes headaches, fatigue, breathing difficulties, death

Question 37

effects of sulfur dioxide and oxides of nitrogen

Answer 37

irritates eyes and lungs, cause breathing difficulties high levels lead to bronchitis react with water in atmosphere to form acid rain, corrode buildings and harm aquatic life & plants

Question 38

effects of unburnt hydrocarbons

Answer 38

cause cancer react with nitrogen oxide to form ozone

Question 39

effect of methane

Answer 39

green house gas, cause global warming

Question 40

effect of ozone

Answer 40

form photochemical smog, irritate eyes and breathing difficulties damage crops

Question 41

formation of acid rain

Answer 41

sulfur dioxide dissolves in water to form sulfurous acid in the presence of o2 in the air, sulfurous acid is oxidised to sulfuric acid in the presence of o2 and water, nitrogen dioxide is converted to nitric acid carbon dioxide dissolves in rainwater to form carbonic acid

Question 42

ph of acid rain

Answer 42

4 or less

Question 43

effect of acid rain

Answer 43

react with metals and carbonates, damage metal structures and stone buildings leaches nutrients from soil, cause plants to wither and die. react with aluminium hydroxide in soil, produce al3+ ions which are toxic to plants reduce ph value of natural water bodies to below 4, too acidic for aquatic life to survive

Question 44

catalytic converters

Answer 44

3 steps of redox 1) CO oxidised to CO2 2) Oxides of nitrogen are reduced to nitrogen 3) unburnt hydrocarbons are oxidised to co2 and h2o

Question 45

flue gas desulfurisation

Answer 45

1) sulfur dioxide passed through plant, react with aq suspension of calcium carbonate to form solid calcium sulfite and co2 gas 2) calcium sulfite further oxidised to calcium sulfate by atmospheric oxygen [calcium oxide can also be used]